package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherMapper;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService{

    @Autowired
    private ISeckillVoucherService seckillVoucherService;

    @Autowired
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRPT;
    static {
        SECKILL_SCRPT = new DefaultRedisScript<>();
        SECKILL_SCRPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRPT.setResultType(Long.class);
    }

    /* 使用阻塞队列的老业务逻辑
    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024*1024);
    private static final ExecutorService SECKILL_ORDER_EXECTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init () {
        SECKILL_ORDER_EXECTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable {

        @Override
        public void run() {
            while (true) {
                try {
                    // 1.获取阻塞队列的订单信息
                    // 1.1 获取阻塞队列的第一个元素
                    VoucherOrder voucherOrder = orderTasks.take();
                    // 2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (InterruptedException e) {
                    log.error("处理订单异常:", e);
                }
            }
        }
    }

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        boolean isLock = lock.tryLock();
        // 判断获取锁是否成功
        if (!isLock) {
            // 获取锁失败，返回报错信息
            log.error("不允许重复下单");
        }
        try {
            proxy.createVoucherOrder(voucherOrder);
        } catch (IllegalStateException e) {
            throw new RuntimeException(e);
        } finally {
            // 释放锁
            lock.unlock();
        }
    }*/

    // 使用消息队列的业务逻辑
    private static final ExecutorService SECKILL_ORDER_EXECTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init () {
        SECKILL_ORDER_EXECTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable {
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    // 1.获取消息队列的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAM stream.order >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    // 2.判断消息是否获取成功
                    if (list == null || list.isEmpty()) {
                        // 如果获取失败就说明没有消息，继续下一次循环
                        continue;
                    }
                    // 3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);

                    // 4.创建订单
                    handleVoucherOrder(voucherOrder);
                    // 5.ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常:", e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    // 1.获取pending-list的订单信息 XREADGROUP GROUP g1 c1 COUNT 1  STREAM stream.order 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    // 2.判断pending-list是否获取成功
                    if (list == null || list.isEmpty() || proxy == null) {
                        // 如果获取失败就说明pending-list没有异常，结束循环
                        break;
                    }
                    // 3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);

                    // 4.创建订单
                    handleVoucherOrder(voucherOrder);
                    // 5.ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list异常:", e);
                }
            }
        }
    }


    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        boolean isLock = lock.tryLock();
        // 判断获取锁是否成功
        if (!isLock) {
            // 获取锁失败，返回报错信息
            log.error("不允许重复下单");
        }
        try {
            proxy.createVoucherOrder(voucherOrder);
        } catch (IllegalStateException e) {
            throw new RuntimeException(e);
        } finally {
            // 释放锁
            lock.unlock();
        }
    }



    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        // 获取用户
        Long userId = UserHolder.getUser().getId();
        // 获取订单id
        long orderId = redisIdWorker.nextId("order");
        // 1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(),
                String.valueOf(orderId)
        );

        // 2.判断结果是否为0
        int r = result.intValue();
        if (r != 0) {
            // 2.1 不为0，代表没有购买资格
            return Result.fail(r == 1 ?"库存不足":"不能重复下单");
        }
        // 3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        return Result.ok(orderId);
    }
    /*@Override
    public Result seckillVoucher(Long voucherId) {
        // 获取用户
        Long userId = UserHolder.getUser().getId();
        // 1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString()
        );

        // 2.判断结果是否为0
        int r = result.intValue();
        if (r != 0) {
            // 2.1 不为0，代表没有购买资格
            return Result.fail(r == 1 ?"库存不足":"不能重复下单");
        }
        // 2.2 结果为0，就把下单信息保存到阻塞队列
        long orderId = redisIdWorker.nextId("order");
        VoucherOrder voucherOrder = new VoucherOrder();
        voucherOrder.setId(orderId);
        voucherOrder.setUserId(userId);
        voucherOrder.setVoucherId(voucherId);
        // 2.3 将结果放入阻塞队列
        orderTasks.add(voucherOrder);

        // 3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        return Result.ok(orderId);
    }*/

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        // 逻辑层面完成一人一单的结果
        Long userId = voucherOrder.getUserId();

        int count = query().eq("user_id",userId).eq("voucher_id",voucherOrder.getVoucherId()).count();
        if (count > 0) {
            // 该用户已经购买过了
            log.error("用户已经购买过一次了");
            return;
        }
        // 5.扣减库存
        // 使用乐观锁解决超卖问题
        boolean success = seckillVoucherService.update().
                setSql("stock = stock - 1")
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock",0). // where voucher_id = ? and stock > 0
                        update();
        // 5.1 扣减失败
        if (!success) {
            log.error("库存不足");
            return;
        }
        save(voucherOrder);
    }

    /*@Override
    public Result seckillVoucher(Long voucherId) {
        // 1.查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        // 2.判断秒杀活动是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            // 2.1 活动尚未开始
            return Result.fail("秒杀活动尚未开始");
        }
        // 3.判断秒杀活动是否结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            // 3.1 活动已经结束
            return Result.fail("秒杀活动已经结束");
        }
        // 4.判断库存是否充足
        if (voucher.getStock() < 1) {
            // 4.1 库存不足
            return Result.fail("库存不足");
        }

        Long userId = UserHolder.getUser().getId();
//        synchronized (userId.toString().intern()) {
//            // 事务采用的是代理对象，这里也需要采用Aop代理对象，由Spring管理
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//        }
        *//* 使用自定义分布式锁创建锁对象
         SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
           获取锁
        boolean isLock = lock.tryLock(1200);*//*

        // 创建锁
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        boolean isLock = lock.tryLock();
        // 判断获取锁是否成功
        if (!isLock) {
            // 获取锁失败，返回报错信息
            return Result.fail("不允许重复下单");
        }
        try {
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } catch (IllegalStateException e) {
            throw new RuntimeException(e);
        } finally {
            // 释放锁
            lock.unlock();
        }
    }*/

    /*@Transactional
    public Result createVoucherOrder(Long voucherId) {
        // 逻辑层面完成一人一单的结果
        Long userId = UserHolder.getUser().getId();

        int count = query().eq("user_id",userId).eq("voucher_id",voucherId).count();
        if (count > 0) {
            // 该用户已经购买过了
            return Result.fail(("用户已经购买过一次了"));
        }
        // 5.扣减库存
        // 使用乐观锁解决超卖问题
        boolean success = seckillVoucherService.update().
                setSql("stock = stock - 1")
                .eq("voucher_id", voucherId).gt("stock",0). // where voucher_id = ? and stock > 0
                        update();
        // 5.1 扣减失败
        if (!success) {
            return Result.fail("库存不足");
        }

        // 6.创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        // 6.1 订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        // 6.2 用户id
        voucherOrder.setUserId(userId);
        // 6.3 代金券id
        voucherOrder.setVoucherId(voucherId);
        save(voucherOrder);

        // 7.返回订单信息
        return Result.ok(orderId);
    }*/
}
